Merge pull request #97 from autonomys/feat/back-hot-cache

File download cache

backend/package.json

@@ -18,6 +18,7 @@
     "@polkadot/types": "^13.0.1",
     "@polkadot/util-crypto": "^13.0.2",
     "@types/express": "^4.17.21",
+    "@types/lru-cache": "^7.10.10",
     "body-parser": "^1.20.2",
     "cors": "^2.8.5",
     "db-migrate": "^0.11.14",

backend/src/services/downloadCache/index.ts

@@ -0,0 +1,42 @@
+import { LRUCache } from 'lru-cache'
+import { bufferToAsyncIterable } from '../../utils/async.js'
+
+const ONE_GB = 1024 ** 3
+
+const cache = new LRUCache<string, Buffer>({
+  maxSize: Number(process.env.MAX_CACHE_SIZE ?? ONE_GB),
+})
+
+const has = (cid: string) => {
+  const has = cache.has(cid)
+  return has
+}
+
+const get = (cid: string) => {
+  const value = cache.get(cid)
+  if (!value) {
+    return null
+  }
+
+  return bufferToAsyncIterable(value)
+}
+
+const set = async function* (
+  cid: string,
+  value: AsyncIterable<Buffer>,
+): AsyncIterable<Buffer> {
+  let buffer = Buffer.alloc(0)
+  for await (const chunk of value) {
+    buffer = Buffer.concat([buffer, chunk])
+    yield chunk
+  }
+  cache.set(cid, buffer, {
+    sizeCalculation: (value) => value.length,
+  })
+}
+
+export const downloadCache = {
+  has,
+  get,
+  set,
+}

backend/src/useCases/objects/files.ts

@@ -22,7 +22,11 @@ import {
 } from '../../models/uploads/upload.js'
 import { AwaitIterable } from 'interface-store'
 import { BlockstoreUseCases } from '../uploads/blockstore.js'
-import { asyncIterableToPromiseOfArray } from '../../utils/async.js'
+import {
+  asyncIterableToPromiseOfArray,
+  bufferToAsyncIterable,
+} from '../../utils/async.js'
+import { downloadCache } from '../../services/downloadCache/index.js'
 
 const generateFileArtifacts = async (
   uploadId: string,
@@ -215,6 +219,7 @@ const downloadObject = async (
   if (!metadata) {
     throw new Error(`Metadata with CID ${cid} not found`)
   }
+  const CACHE_THRESHOLD = 150 * 1024 * 1024
 
   const pendingCredits = await UsersUseCases.getPendingCreditsByUserAndType(
     reader,
@@ -224,27 +229,38 @@ const downloadObject = async (
   if (pendingCredits < metadata.totalSize) {
     throw new Error('Not enough download credits')
   }
+  if (downloadCache.has(cid)) {
+    return downloadCache.get(cid)!
+  }
 
   if (metadata.type === 'folder') {
     const zip = await retrieveAndReassembleFolderAsZip(
       reader,
       new PizZip(),
       cid,
     )
-    return [
-      zip.generate({
-        type: 'nodebuffer',
-      }),
-    ]
+    const downloadedBuffer = zip.generate({ type: 'nodebuffer' })
+    if (metadata.totalSize < CACHE_THRESHOLD) {
+      downloadCache.set(cid, bufferToAsyncIterable(downloadedBuffer))
+    }
+    return bufferToAsyncIterable(downloadedBuffer)
   }
 
-  const data = retrieveAndReassembleFile(metadata)
+  if (downloadCache.has(cid)) {
+    return downloadCache.get(cid)!
+  }
+
+  let data = retrieveAndReassembleFile(metadata)
   await UsersUseCases.registerInteraction(
     reader,
     InteractionType.Download,
     metadata.totalSize,
   )
 
+  if (metadata.totalSize < CACHE_THRESHOLD) {
+    data = downloadCache.set(cid, data)
+  }
+
   return data
 }
 

backend/src/utils/async.ts

@@ -39,3 +39,11 @@ export const asyncIterableToPromiseOfArray = async <T>(
   }
   return result
 }
+
+export const bufferToAsyncIterable = (
+  buffer: Buffer,
+): AsyncIterable<Buffer> => {
+  return (async function* () {
+    yield buffer
+  })()
+}

backend/yarn.lock

@@ -1942,6 +1942,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/lru-cache@npm:^7.10.10":
+  version: 7.10.10
+  resolution: "@types/lru-cache@npm:7.10.10"
+  dependencies:
+    lru-cache: "npm:*"
+  checksum: 10c0/ab85558867cb059bebd42074c1cd517eb41efb1db22b9d26dfdc58df01c83ff9c212a562b4ec3d5936418ffb03e626a0f30463026aa5fb5ced41e3b4b4af057f
+  languageName: node
+  linkType: hard
+
 "@types/markdown-it@npm:^14.1.1":
   version: 14.1.2
   resolution: "@types/markdown-it@npm:14.1.2"
@@ -3012,6 +3021,7 @@ __metadata:
     "@types/cors": "npm:^2.8.17"
     "@types/express": "npm:^4.17.21"
     "@types/jest": "npm:^29.5.12"
+    "@types/lru-cache": "npm:^7.10.10"
     "@types/multer": "npm:^1"
     "@types/node": "npm:^22.3.0"
     "@types/pg": "npm:^8.11.10"
@@ -5348,6 +5358,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"lru-cache@npm:*":
+  version: 11.0.2
+  resolution: "lru-cache@npm:11.0.2"
+  checksum: 10c0/c993b8e06ead0b24b969c1dbb5b301716aed66e320e9014a80012f5febe280b438f28ff50046b2c55ff404e889351ccb332ff91f8dd175a21f5eae80e3fb155f
+  languageName: node
+  linkType: hard
+
 "lru-cache@npm:^10.0.1, lru-cache@npm:^10.2.0":
   version: 10.4.3
   resolution: "lru-cache@npm:10.4.3"

frontend/src/components/Files/ObjectDownloadModal.tsx

@@ -53,7 +53,7 @@ export const ObjectDownloadModal = ({
     const passwordToUse = password ?? undefined;
 
     try {
-      fetchFile(metadata.dataCid, passwordToUse);
+      await fetchFile(metadata.dataCid, passwordToUse);
       onClose();
     } catch (e) {
       if (e instanceof InvalidDecryptKey) {